Screenshots of proprietary software and websites are copyrighted. It is impossible to create public domain or free screenshots of proprietary software or websites. These screenshots are being used under "fair use" to illustrate how to use certain proprietary software.

Required because:

This book is being written to teach beginners how to use specific proprietary computer software. It is basically impossible to teach this without illustrations - i.e. screenshots. For all practical purposes, this educational book requires the use of screenshots.

This is a screenshot of copyrighted computer software, and the copyright for its contents is most likely held by the author(s) or the company that created the software. It is believed that the use of a limited number of web-resolution screenshots:

for identification of, and critical commentary on, the software in question